It also sets up what could be a rollicking first day in the Legislature on Feb. 20 if Fischbach attempts to take her seat and Democrats try to stop her.

Since no one knows if Fischbach will attempt to take her seat in the Senate when the session begins, there's nothing to rule on and "no more than a hypothetical injury," Judge John Guthmann wrote as he dismissed a lawsuit over the matter. "This is not the right case, the right plaintiff, the right time or the right legal context to consider defendant's eligibility to serve in the Minnesota Senate."

Guthmann had been asked to rule on a complaint by a resident of Fischbach's Senate district, Destiny Dusosky of Sauk Rapids, Minn. Dusosky argued the Republican lawmaker is violating the state constitution's separation of powers clause and a revision from the 1970s that prohibits legislators from holding other offices.

Chief Judge John H. Guthmann speaks during a motion hearing in the civil lawsuit by constituent Destiny Dusoskyon Tuesday, February 6, 2018, at the Ramsey County Courthouse in St. Paul, Minn.Renee Jones Schneider | Pool via Star Tribune

"I respectfully disagree with the court's decision," Dusosky's lawyer, Charlie Nauen said Monday. "When you boil it down the district court did not address the fundamental constitutional principle which we sued about requiring the separation of powers between branches of government, which is, I believe, is a question for the court, not for the legislature."

Nauen wanted the court to force Fischbach to resign her Senate seat, which she has held since 1996. He is also seeking a temporary injunction to block her from voting in the Senate when the 2018 legislative session begins in two weeks.

"Unless this court decides, there's going to be an asterisk behind every single vote, procedural vote, committee vote, every single action," he said.

As Senate president, Fischbach ascended to the office of lieutenant governor to fill the vacancy created when DFL Gov. Mark Dayton appointed Tina Smith early last month to replace Al Franken as U.S. Senator.

Fiscchbach has declined the lieutenant governor salary and has not been sworn in. She contends that a 1898 Minnesota Supreme Court decision allows her to hold both jobs, and that the later constitutional revisions don't change the core reasoning of that ruling.

Her lawyer, Kevin Magnuson, argued last week that the court should not be deciding who can be a state senator.

"The real power to make that determination lies with the Senate, solely with the Senate," Magnuson said. "So, I don't think that you can enjoin the Senate, I don't think you can order them not to seat Sen. Fischbach."

The case has critical implications for control of the Minnesota Senate. Republicans currently hold a 34-32 advantage, pending the result of a special election Monday. If Democrats can hold that seat, then a court ruling against Fischbach would force a special election in her district that could potentially flip control.

Guthmann doubted the ability of the courts to toss a lawmaker based on a citizen lawsuit. With him saying it's up to the Senate to decide whom to seat, there could be a showdown next week when the Legislature reconvenes. Senate Minority Leader Tom Bakk, DFL-Cook, has said he expects any bill Fischbach votes on would be subject to a court challenge if her role is not clear.

Senate Democrats could try to force a vote on Fischbach's right to hold a Senate seat, and the outcome of that vote may depend on a special election.